AP Photo/Stephan SavoiaAttorney David Meier, at right with pen in hand, was appointed by Gov. Deval Patrick to lead the review of drug convictions that might have been compromised by a former chemist employed at the William A. Hinton State Laboratory Institute, a state drug lab in the Jamaica Plain section of Boston. In this photo, taken earlier this week, Meir leads a meeting of state police, state and federal prosecutors and defense attorneys, among others, at the Massachusetts Executive Office of Public Safety and Security in Boston.

BOSTON — Was she trying to help prosecutors win drug convictions? Did she have a law-and-order streak that prevented her from doing her job dispassionately?

Investigators have not released a motive regarding what possessed disgraced state chemist Annie Dookhan, who resigned earlier this year from the William A. Hinton State Laboratory Institute in Boston, to allegedly tamper with tens of thousands of drug samples used as evidence in criminal cases. But the Franklin woman has accepted responsibility for her alleged transgressions, according to a police report leaked to Massachusetts media outlets.

Dookhan, 34, has yet to be charged with any crimes even though she is at the center of a high-profile scandal that so far has resulted in the resignation of the state's health commissioner and negative publicity for the Patrick administration, which closed Hinton lab in August amidst mounting allegations.

The governor last week appointed David Meier, a former Suffolk County homicide prosecutor, to head up an ad-hoc office responsible for reviewing thousands of criminal cases potentially tainted by mishandled drug evidence.

On Thursday, Patrick said he expected criminal charges to be filed in connection with the case, but he did not indicate when that might happen.

Dookhan said the mishandling of some 60,000 drug samples, more than half of which were used as evidence in criminal cases, was her fault — and hers alone. Dookhan said she did not want the state lab "to get into trouble," according to a copy of a state police investigation report obtained by the Boston Globe. The Associated Press has also obtained a copy of the report, which state officials have declined to release.

The report, authored by troopers assigned to Attorney General Martha Coakley's office and the State Police Forensic Services Group, was not authorized to be released, state police spokesman David Procopio said Wednesday. "Please note that the Massachusetts State Police did not provide the report to the outlet that has obtained it, and as a rule, we would not release an evidentiary report at this stage of any ongoing criminal investigation," he said.

Gov. Deval Patrick

The report includes information that could be damning for Dookhan, including acknowledgments that she "messed up bad" and "screwed up big time," the Globe reports.

Dookhan resigned in March from Hinton lab in the Jamaica Plain section of Boston. She has avoided the media since then, though the leaked report is bound to fuel more interest in the case. Mulitple news agencies have requested copies of the report, Procopio said, adding that state police officials have no plans of publicly releasing documents pertaining to an active investigation.

Police claim Dookhan admitted to faking drug sample results for more than two years. She also forged signatures and skipped proper procedures in handling the samples, according to the report. Some co-workers told lab supervisors they were concerned about Dookhan's involvement in a high number of drug cases, but supervisors failed to intervene, investigators said.

Dookhan insisted she acted alone. "I messed up. I messed up bad. It's my fault. I don't want the lab to get in trouble," she told troopers, according to the report obtained by the Globe.

During Dookhan's 9-year tenure at the lab, from 2003 until March, she tested more than 60,000 drug samples that were used as evidence in cases involving about 34,000 defendants, police said. She resigned amid an internal investigation by the state Department of Public Health, which transferred control of Hinton lab to state police in July. Gov. Deval L. Patrick shut down the lab a month later after it became clear that tens of thousands of samples may have been mishandled by Dookhan, casting a pall over thousands of criminal cases involving potentially tainted evidence.

Investigators have identified 1,141 Massachusetts inmates currently incarcerated in jails or prisons whose cases included evidence analyzed by Dookhan. At least 20 drug defendants have already been released or had bail reductions or sentence suspensions because of the chemist's involvement. Attorneys have said they are bracing for the possibility of dozens of legal challenges.

Attorney Rosemary Scapicchio

"I can't imagine she could have been this corrupt without someone noticing," Boston-based defense attorney Rosemary C. Scapicchio told the Associated Press.

Scapicchio, who represents several defendants whose samples were handled by Dookhan, has called for a federal probe. "The investigation needs to go deeper than Annie Dookhan to get to the point of 'How did she get away with it?'" the lawyer told AP.

Anne Goldbach, forensic services director for the state Committee for Public Counsel Services, said in a memorandum to defense attorneys that the "unfolding investigation indicates that some or all of the evidence from (Hinton lab) is tainted and cannot support prosecutions."

Goldbach said all drug cases involving evidence processed at Hinton should be carefully scrutinized in light of emerging details about the Dookhan case. "Every client facing charges based on evidence from this lab needs advice from counsel about how the misconduct being revealed at the lab may impact the case. Every client whose conviction was based on testing done by this chemist (Dookhan) also needs advice from counsel about how the misconduct at the lab impacted their case," she said.

Investigators said things began to unravel for Dookhan last year, when she was caught forging a colleague's initials on paperwork after taking drug samples from evidence. A lab supervisor told police that he believed Dookhan had suffered a mental breakdown.

Investigators said Dookhan admitted to turning negative drug samples into positive samples. In some cases, authorities said, she eyeballed samples, determining they were drugs without actually testing them. "I intentionally turned a negative sample into a positive a few times," Dookhan said in a signed statement to troopers probing the case.

When police suggested she hire an attorney, Dookhan told them she was having marital problems and could not afford a lawyer, the Globe reports. State police Detective Lt. Robert Irwin, an investigator with Coakley's office, asked Dookhan if she ever had any "bad thoughts." Dookhan replied that the harm she was causing people had crossed her mind "every now and then," Irwin wrote in the report. "I then asked her if she had thought of harming herself. She said no."

Dookhan is also accused of lying about her academic credentials. Her resume states that she received a master's degree in chemistry from UMass-Boston, but university officials said they have no record of granting her a diploma. However, Dookhan did receive an undergraduate degree from UMass-Boston.

Goldbach said Hinton lab handled drug evidence for prosecutions in nine counties, including thousands of defendants from the North Shore, South Shore, South Coast and the Cape and islands. The possibility of evidence tampering dates back to at least 2003, the year Dookhan was hired, Goldbach said.

Material from the Associated Press, Boston Globe, Boston Herald, The Republican and State House News Service was used in this report.